1. Field of the Invention
This invention relates both to solving the disposal problem of heavy ends waste generated from the manufacture of chlorinated hydrocarbons such as ethylene dichloride and/or vinyl chloride, and to improving epoxy resin by modifying it with a low odor, polysulfide polymer. Herein, a process is disclosed for using the heavy ends waste to produce polysulfide-epoxy co-polymers.
2. Information Disclosure Statement
The production of resinous products by co-reacting polysulfide polymers with polyepoxide resins in the presence of catalyst is well known in the prior art. In 1957, U.S. Pat. No. 2,789,958 disclosed reacting a resinous reaction between the mercaptan groups of polysulfide and the oxirane groups of the polyepoxide which forms the basis for co-reacting polysulfide polymers with epoxy resins. Despite their success as tough, chemical resistant coatings and adhesives, the polysulfide-epoxy system suffers from a mercaptan odor which persists until the system begins to cure.
Since then, methods of producing a low odor polysulfide-epoxy co-polymer have been disclosed. In 1985, G.B. Patent No. 2,162,189 disclosed a procedure to prepare a stable liquid polysulfide-epoxy prepolymer which has a long pot life before curing with a hardener. This liquid prepolymer, however, is made from pure starting chemicals which increase costs. Furthermore, the polysulfide polymer must be co-reacted with a molar excess of epoxy resin to reduce the odor; prior to the co-reaction, an offensive odor exists. Similar methods and products have been described in E. A. Peterson, Polysulfides, Adhesive Materials: Chemical Families pp 138-142 and T. M. Rees et al., The Modern Approach to Modifying Epoxy Resins Using Liquid Polysulfides: Part 1, JOCCA pp. 39-46 (1988). Again, these disclosures relate to reducing odor by co-reacting a polysulfide polymer manufactured from pure starting chemicals with epoxy resin. Thus, the prior art fails to disclose a method for using heavy ends waste to produce a low odor polysulfide polymer which can be co-reacted with a molar excess of epoxy resin to further reduce odor.